RU2673237C2 - Method of obtaining purified compound - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method for producing a purified compound of formula (II), comprising preparing a reaction mixture containing a compound of formula (I) from a crude compound of formula (II), filtering the resulting reaction mixture, reacting the resulting reaction mixture with water and isolating the purified compound of formula (II).EFFECT: novel method of obtaining a purified compound of formula (II) has been developed, which enables to obtain the target compound with high purity of 96 % or more.1 cl, 1 ex

Description

FIELD OF THE INVENTION

[0001]

The present invention provides a method for producing a purified compound.

State of the art

[0002]

Patent Document 1 describes that 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H) -one as an intermediate 2- (7-fluoro-4-propargyl-2H-1,4-benzoxazine -3 (4H) -on-6-yl) -4,5,6,7-tetrahydroisoindole, useful as an intermediate compound as a herbicide.

Prior Art Document

Patent document

[0003]

Patent Document 1: Japanese Patent Laid-Open Publication No. 5-97826

SUMMARY OF THE INVENTION

Problems Solved by the Invention

[0004]

A process is required to produce a high purity compound, usually such as 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H) -one, represented by formula (II):

where R ³ represents a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, and X represents a halogen atom.

Problem Solving Tools

[0005]

The present invention includes the following aspects of the invention.

[1] A method for producing a purified compound represented by formula (II), comprising preparing a reaction mixture containing a compound represented by formula (I) from a crude compound represented by formula (II), and reacting the resulting reaction mixture containing a compound represented by formula ( I), with water:

where each R ¹ and R ² independently from each other represents an alkyl group, or R ¹ and R ^{2 are} connected to each other, forming a ring structure with a carbon atom to which R ¹ and R ² are connected; R ³ represents a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, and X represents a halogen atom,

wherein R ³ and X have the same meanings as given above.

[0006]

[2] The production method described in paragraph [1], comprising obtaining a reaction mixture containing a compound represented by formula (I) from a crude compound represented by formula (II), filtering the resulting reaction mixture containing a compound represented by formula (I ), and the interaction of the solution obtained in this way with water.

Description of Embodiments

[0007]

Examples of the alkyl group in R ¹ and R ² are an alkyl group containing from 1 to 6 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert- butyl group, isobutyl group, n-pentyl group and n-hexyl group, and preferably an alkyl group containing from 1 to 5 carbon atoms is present as an alkyl group, and more preferably a methyl group or isobutyl group.

Examples of the ring structure formed by the interconnection of R ¹ and R ² in combination with the carbon atom to which R ¹ and R ² are bonded are a cyclohexane ring and a cyclopentane ring.

Examples of the alkenyl group in R ³ are an alkenyl group containing from 2 to 6 carbon atoms, such as a vinyl group and an allyl group, and preferably an alkenyl group containing from 2 to 4 carbon atoms is present as an alkenyl group, and more preferably an allyl group.

Examples of the alkynyl group in R ³ are an alkynyl group containing from 2 to 6 carbon atoms, such as an ethynyl group and a 2-propynyl group, and preferably an alkynyl group containing from 2 to 4 carbon atoms is present as an alkynyl group, and more preferably 2 propynyl group.

R ³ preferably represents a hydrogen atom.

Examples of the halogen atom X are a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and preferably a fluorine atom is present as the halogen atom.

X is preferably attached at position 7, and a fluorine atom is preferably attached at position 7.

[0008]

An example of a compound represented by formula (II) (hereinafter sometimes referred to as “compound (II)”) is 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H) -one.

The crude compound (II) can be obtained, for example, according to the method described in Japanese laid patent application No. 62-212375. The purity of the crude compound (II) is usually from 80% to 95%.

[0009]

Examples of the compound represented by formula (I) (hereinafter sometimes referred to as “compound (I)”) are 6- (1,3-dimethylbutylideneamino) -7-fluoro-2H-1,4-benzoxazin-3 (4H) -one and 6- (1-methylethylidenamino) -7-fluoro-2H-1,4-benzoxazin-3 (4H) -one.

[0010]

Compound (I) is preferably prepared by reacting a crude compound (II) with a ketone compound. The reaction of the crude compound (II) with a ketone compound is usually carried out by mixing the crude compound (II) with a ketone compound. The reaction is preferably carried out in the presence of an acid. In addition, the reaction can also be carried out in the presence of a solvent.

The reaction temperature is usually from 60 ° C to 200 ° C, and preferably from 70 ° C to 150 ° C.

[0011]

Examples of the ketone compound are acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, dibutyl ketone, cyclopentanone and cyclohexanone, and methyl isobutyl ketone is preferably used as the ketone compound.

The amount of ketone compound used is usually from 1 mol to 100 mol, based on 1 mol of the crude compound (II). The ketone compound can be used in combination with a solvent.

[0012]

Examples of the acid are hydrochloric acid, sulfuric acid, acetic acid, p-toluenesulfonic acid and methanesulfonic acid, and p-toluenesulfonic acid is preferably used as the acid.

The amount of acid used is usually from 0.001 mol to 0.01 mol, based on 1 mol of the crude compound (II).

[0013]

Examples of the solvent include aromatic compounds such as toluene and xylene; halogenated compounds such as methylene chloride; aliphatic hydrocarbon compounds such as hexane and heptane; as well as them and mixtures.

The amount of solvent used is usually from 1 wt. hours to 50 wt. hours, preferably from 1 wt. hours to 30 wt. hours and preferably from 1 wt. hours to 20 wt. hours per 1 wt. including crude compound (II).

[0014]

The reaction mixture obtained by reacting compound (II) with a ketone compound can, for example, be concentrated and filtered to isolate compound (I). The resulting reaction mixture can be reacted with water, and compound (I) can be isolated and reacted with water. Preferably, the resulting reaction mixture is filtered, and the solution thus obtained is reacted with water.

[0015]

The interaction of compound (I) with water is preferably carried out by mixing compound (I) and water. Mixing is preferably carried out by adding water to compound (I).

The reaction of compound (I) with water is preferably carried out in the presence of an acid or solvent.

The reaction temperature is usually from 0 ° C to 100 ° C and preferably from 20 ° C to 80 ° C.

The interaction can be carried out in a nitrogen atmosphere. In addition, the interaction can be carried out under reduced pressure.

The amount of water used is usually from 1 mol to 100 mol, and preferably from 1 mol to 10 mol, based on 1 mol of compound (I).

[0016]

Examples of the acid include the aforementioned acids.

The amount of acid used is usually from 0.001 mol to 1 mol, and preferably from 0.001 mol to 0.01 mol, based on 1 mol of compound (I).

[0017]

Examples of the solvent include acetone, methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone and methyl isobutyl ketone, and methyl isobutyl ketone is preferably used as the solvent.

The amount of solvent used is usually from 1 wt. hours to 50 wt. hours, preferably 1 wt. hours to 30 wt. hours and preferably 1 wt. hours to 20 wt. hours per 1 wt. including compound (I).

[0018]

The reaction mixture obtained by reacting compound (I) with water can, for example, be concentrated and filtered to isolate purified compound (II).

The purified compound (II) has a higher purity than the crude compound (II). The purity of the purified compound (II) is usually 96% or more.

According to the present invention, a high purity compound represented by the formula (II) can be obtained.

[Examples]

[0019]

The present invention will now be described in more detail with examples. In addition, purity is determined by the ratio of the peak area of a given compound to the total peak area, excluding solvent peaks, according to the results of analysis by high resolution liquid chromatography.

[0020]

Example 1

Under a nitrogen atmosphere, 25 g (95.3% purity) of crude 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H) -one, 190 g of methyl isobutyl ketone and 0.1 g of p-toluenesulfonic acid were placed in a flask acids. The mixture was heated to 110 ° C under reduced pressure, followed by heating under reflux and dehydration for 5 hours. After dehydration, 86 g of methyl isobutyl ketone was evaporated, and then filtration and washing were carried out to obtain a solution (16.0%, 100% yield) of 6- (1,3-dimethylbutylideneamino) -7-fluoro-2H-1,4-benzoxazine-3 (4H) -one in methyl isobutyl ketone.

126 g of the resulting solution was placed in a flask, which was heated to 100 ° C under reduced pressure, and 58 g of methyl isobutyl ketone was evaporated. 4 g of water was added to the resulting mixture at 70 ° C, and after the reaction, the mixture was concentrated under reduced pressure. The resulting suspension was filtered, washed with methanol and water, and purified to give 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H) -one (99.4% purity, 97% yield).

Industrial applicability

[0021]

According to the present invention, a high purity compound represented by the formula (II) can be obtained.

Claims (6)

1. A method of obtaining a purified compound represented by formula (II), comprising obtaining a reaction mixture containing a compound represented by formula (I) from a crude compound represented by formula (II), filtering the resulting reaction mixture containing a compound represented by formula (I) the interaction of the obtained reaction mixture containing the compound represented by formula (I) with water and the allocation of the purified compounds of formula (II):

where each R ¹ and R ² independently from each other represents an alkyl group, or R ¹ and R ^{2 are} connected to each other, forming a ring structure with a carbon atom to which R ¹ and R ² are connected; R ³ represents a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, and X represents a halogen atom,

where R ³ and X have the same meanings as presented above. 2. The production method according to claim 1, wherein the purity of the crude compound of formula (II) is from 80% to 95.3%, and the purity of the purified compound (II) is 96% or more.